Peter, this is not necessarily relevant to Artyfriend but raised calcium in the blood can indicate active bone mets.
Arty, a few years ago, most men on long term HT with significant bone mets were given Zometa (a bisphosphonate) to reduce the risk of bone thinning. I am not sure why it isn't routine any more - perhaps cost but more likely that the side effects can be quite significant? If they do recommend Zometa for your OH, ask the nurse or GP whether you should arrange a dental appointment before he starts.